A New Species of the Genus Isobactrus (Acari : Halacaridae) from Ponape, Micronesia, with a Special Reference to Infrageneric Character State Distribution

Abstract

A new species of the genus Isobactrus is described from Ponape Island under the name of Isobactrus ponapensis sp. nov. The new species closely resembles I. pacificus Bartsch, 1989 and I. luxtoni Bartsch, 1992. But, I. ponapensis is distinguished from these two species by the anal foramen placed partly on the striated membranous cuticle and the absence of outlying perigenital setae in the male. The genus Isobactrus is recorded from Micronesia for the first time. Character state distribution for 22 diagnostic characters in the genus is also given. Isobactrus species from the Mid-Pacific region are uniquely characterized by the absence of the lateral seta on the third coxal region and by having two setae on the first genu.